Full hoop blade track with interstage cooling air

ABSTRACT

A gas turbine engine includes a turbine having a plurality of vanes, a plurality of blades, a turbine shroud arranged around the vanes and blades, and a turbine case arranged around the turbine shroud. The turbine shroud is sized to block combustion products from passing over the blades without pushing the blades to rotate. The turbine shroud includes a runner arranged around the blades and a carrier arranged around the runner.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to gas turbine engines, andmore specifically to turbine shrouds used in gas turbine engines.

BACKGROUND

Gas turbine engines are used to power aircraft, watercraft, powergenerators, and the like. Gas turbine engines typically include acompressor, a combustor, and a turbine. The compressor compresses airdrawn into the engine and delivers high pressure air to the combustor.In the combustor, fuel is mixed with the high pressure air and isignited. Products of the combustion reaction in the combustor aredirected into the turbine where work is extracted to drive thecompressor and, sometimes, a fan assembly. Left-over products of thecombustion are exhausted out of the turbine and may provide thrust insome applications.

Compressors and turbines typically include alternating stages of staticvane assemblies and rotating wheel assemblies. The rotating wheelassemblies include disks carrying blades around their outer edges. Whenthe rotating wheel assemblies turn, tips of the blades move along bladetracks included in static shrouds that are arranged around the rotatingwheel assemblies. Such static shrouds may be coupled to an engine casethat surrounds the compressor, the combustor, and/or the turbine.

Some shrouds positioned in the turbine may be exposed to hightemperatures from products of the combustion reaction in the combustor.Such shrouds sometimes include components made from materials that havedifferent coefficients of thermal expansion; i.e. metallic, ceramics,and/or composites. Due to the differing coefficients of thermalexpansion, the components of some turbine shrouds expand at differentrates when exposed to combustion products. Integrating such componentscan present challenges for assembly and operation of turbine shrouds.

SUMMARY

Gas turbine engines typically include a compressor, a combustor, and aturbine. The compressor compresses air drawn into the engine anddelivers high pressure air to the combustor. In the combustor, fuel ismixed with the high pressure air and is ignited. Products of thecombustion reaction in the combustor are directed into the turbine wherework is extracted to drive the compressor and, sometimes, a shaft.Left-over products of the combustion are exhausted out of the turbineand may provide thrust in some applications.

In illustrative embodiments, the turbine includes a plurality ofrotating blades and a turbine shroud arranged around the blades to blockgas from passing over the blades without interacting with the blades.The turbine shroud defines an internal buffer chamber that receivescooling air to control a temperature of the turbine shroud.

In illustrative embodiments, the turbine includes a cooling systemconfigured to direct pressurized cooling air into the buffer chamber tocool the turbine shroud. The cooling system illustratively includes atleast one hollow insert pin extending through the turbine case and theturbine shroud into the buffer chamber to allow pressurized cooling airto pass through the turbine case and the turbine shroud into the bufferchamber.

In illustrative embodiments, the cooling system further includes animpingement plate positioned in the buffer chamber to separate theannular buffer chamber into an outer chamber and an inner chamberlocated radially between the outer chamber and the annular runner. Thepressurized cooling air is conducted through the hollow insert pin intothe outer chamber. The outer chamber is configured to uniformlydistribute the air in the buffer chamber before the air is conductedinto the inner chamber. The impingement plate illustratively includes aplurality of diffusion holes extending through the impingement plate andconfigured to direct the pressurized cooling air in the outer chamberinto the inner chamber and toward a runner included in the turbineshroud.

These and other features of the present disclosure will become moreapparent from the following description of the illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cut-away perspective view of a gas turbine engine includinga turbine section, the turbine section including a rotating wheelassembly, a turbine shroud arranged around the rotating wheel assembly,and a turbine case arranged around the turbine shroud;

FIG. 2 is a detail view of FIG. 1 showing that the gas turbine engineincludes a plurality of outer insert pins that extend through theturbine case into the turbine shroud to block rotation of the turbineshroud relative to the turbine case and that the turbine shroud includesa carrier and an annular runner positioned radially between the carrierand blades of the rotating wheel assembly to block combustion productsfrom passing over the blades;

FIG. 3 is a partial perspective view of the gas turbine engine of FIG. 1cut away to show (i) that the outer insert pins extend through theturbine case and the carrier included in the turbine shroud to blockrotation of the turbine shroud relative to the turbine case and toprovide centering of the carrier to the turbine case and suggesting thatthe outer insert pin is hollow to allow pressurized cooling air to passthrough the turbine case and the carrier into a buffer chamber formed bythe turbine shroud to cool the annular runner and (ii) that a healthmonitoring system of the gas turbine engine includes a sensor extendingthrough the hollow outer insert pin to measure properties of the bufferchamber;

FIG. 4 is an exploded perspective view of certain components of theturbine section included in the gas turbine engine of FIGS. 1 and 2showing that the turbine section includes the turbine case formed toinclude a plurality of outer keyways, the carrier formed to include aplurality of outer pin receivers and a plurality of inner keyways spacedapart from the outer pin receivers, the plurality of outer insert pinsadapted to extend through the outer keyways of the turbine case and intothe outer pin receivers of the carrier, the annular runner formed toinclude a plurality of inner pin receivers, and a plurality of innerinsert pins adapted to extend through the inner keyways of the carrierinto the annular runner;

FIG. 5 is a cross-sectional view of the carrier included in the turbineshroud of FIG. 3 showing that the carrier includes a forward section, anaft section, and a midsection extending axially therebetween, showingthat the outer pin receivers and the outer keyways are formed in themidsection of the annular runner, and showing that a high-pressurecooling air passage is formed in the forward section of the carrier;

FIG. 6 is a cross-sectional view of the annular runner included in theturbine shroud of FIG. 3 showing that the annular runner includes aforward section, an aft section, and a midsection extending axiallytherebetween;

FIG. 7 is a partial cross-sectional view of the gas turbine engine ofFIG. 1 showing that the outer insert pins extend through the turbinecase into the outer pin receivers formed in the carrier and that thecarrier is formed to include the high-pressure air passageway at aforward section of the carrier;

FIG. 7A is a view similar to FIG. 7 showing an optional impingementplate positioned in the turbine shroud and showing that the impingementplate is formed to include diffusion holes configured to distributecooling air within the turbine shroud;

FIG. 8 is a partial cross-sectional view of the gas turbine engine ofFIG. 1 showing that the inner insert pins extend through the innerkeyways formed in the carrier into the inner pin receivers formed in theannular runner to block rotation of the carrier relative to the annularrunner and center the annular runner relative to the carrier;

FIG. 9 is an enlarged cross-sectional view of the turbine shroud ofFIGS. 7 and 8 showing piston ring seals positioned between the forwardsections of the carrier and the annular runner;

FIG. 10 is an enlarged cross-sectional view of the turbine shroud ofFIGS. 7 and 8 showing a piston ring seal positioned between the aftsections of the carrier and the annular runner;

FIG. 11 is an enlarged cross-sectional view of the turbine shroud ofFIGS. 7 and 8 showing alternative C-shaped seals positioned between theforward sections of the carrier and the annular runner in place of thepiston ring seals of FIG. 9;

FIG. 12 is an enlarged cross-sectional view of the turbine shroud ofFIGS. 7 and 8 showing an alternative C-shaped seal positioned betweenthe aft sections of the carrier and the annular runner in place of thepiston ring seal of FIG. 10; and

FIG. 13 is an enlarged cross-sectional view of another embodiment of aturbine shroud for use in the gas turbine engine of FIG. 1 showing aW-shaped seal positioned between the forward sections of the carrier andthe annular runner which may replace the piston ring seal arrangement ofFIG. 9.

DETAILED DESCRIPTION OF THE DRAWINGS

For the purposes of promoting an understanding of the principles of thedisclosure, reference will now be made to a number of illustrativeembodiments illustrated in the drawings and specific language will beused to describe the same.

An illustrative gas turbine engine 10 includes a turbo shaft 11, acompressor 13, a combustor 15, and a turbine 17 as shown in FIG. 1. Theturbine 17 includes a turbine case 12 arranged to support a turbineshroud 14 between blades 33 included in the turbine 17 and the turbinecase 12 as shown in FIG. 2. The turbine shroud 14 includes a carrier 16and a runner 18 coupled to the carrier 16 as shown in FIGS. 3 and 4. Insome embodiments, the turbine 17 includes two sets of mount pins 30, 50to locate the runner 18 of the turbine shroud 14; specifically, outerinsert pins 30 are arranged to couple the turbine shroud 14 to theturbine case 12 and inner insert pins 50 are arranged to couple therunner 18 to the carrier 16 as shown in FIG. 4. In some embodiments, theturbine 17 includes a health monitoring system 82 configured to detectand react to changes in the condition of the turbine shroud 14 as shownin FIG. 7. In some embodiments, an optional impingement plate 57 isarranged radially between the carrier 16 and the runner 18 of theturbine shroud 14 to distribute cooling air within the turbine shroud 14onto the runner 18 as shown in FIG. 7A.

FIG. 1 shows the illustrative aerospace gas turbine engine 10 used in anaircraft. The turbo shaft 11 included in the engine 10 powers a gearboxthat transfers power to a propeller or transfers power directly to afan, either of which propels the aircraft. The compressor 13 compressesand delivers air to the combustor 15. The combustor 15 mixes fuel withthe compressed air received from the compressor 13 and ignites the fuel.The hot, high pressure products of the combustion reaction in thecombustor 15 are directed into the turbine 17 and the turbine 17extracts work from the high pressure products to drive the compressor 13and the turbo shaft 11. In other embodiments, the engine 10 includes aone or more of a turbofan, turboshaft, turboprop, or other suitablealternative.

As shown in FIG. 2, the turbine 17 includes turbine vane assemblies 26having a plurality of vanes 36, turbine wheel assemblies 21, 22 having aplurality of blades 31, 33, the turbine shroud 14 arranged around thevanes 36 and the blades 33, and the turbine case 12 arranged around theturbine shroud 14. In the illustrative embodiment, a plurality ofturbine shrouds 14 are arranged around the turbine wheel assemblies 21,22 and the turbine case 12 is arranged around the turbine wheels 21, 22and the turbine shrouds 14.

The vanes 36 of the vane assemblies 26 extend across a flow path 34 ofthe hot, high-pressure combustion products from the combustor 15 todirect the combustion products toward the blades 33 of the turbine wheelassemblies 22. The blades 33 are in turn pushed by the combustionproducts to cause the turbine wheel assemblies 22 to rotate; thereby,driving the rotating components of the compressor 13 and the turbo shaft11. The exemplary turbine shroud 14, shown in FIG. 2, extends around theturbine wheel assembly 22 and is sized to block most combustion productsfrom passing over the blades 33 without pushing the blades 33 to rotate.Combustion products that are allowed to pass over the blades 33 do notpush the blades 33 and such passed-over products contribute to lostperformance within the engine 10.

The turbine case 12 extends circumferentially about a central axis 20 ofthe gas turbine engine 10 as shown in FIG. 1. In the illustrativeembodiment, the turbine case 12 is metallic. The turbine case 12 isformed to include a plurality of outer keyways 28 that extend throughthe turbine case 12 as shown in FIGS. 3, 4, and 7. The outer keyways 28are arranged to receive the outer insert pins 30 that extend through theouter keyways 28 and into the turbine shroud 14 to couple the turbineshroud 14 to the turbine case 12 as shown in FIG. 3. In otherembodiments, the turbine case 12 does not include the outer keyways 28and the turbine shroud 14 is coupled to the turbine case with hangers,fasteners, or any other suitable alternative coupler.

In the illustrative embodiment, the outer keyways 28 extend radiallythrough the turbine case 12 as shown in FIG. 7. In some embodiments, theturbine case 12 includes at least three outer keyways 28 and outerinsert pins 30 to locate the turbine shroud 14 in three dimensionsrelative to the turbine case 12. Illustratively, the outer keyways 28are spaced apart from each other circumferentially about the centralaxis 20 as shown in FIG. 4.

In the illustrative embodiment, the turbine case 12 is formed to includea plurality of bosses 24 as shown in FIG. 7. The bosses 24 areintegrally formed with the turbine case 12 and extend radially outwardaway from the turbine shroud 14. The outer keyways 28 extend through thebosses 24 and the outer insert pins 30 are arranged to extend throughthe bosses 24.

The turbine shroud 14 extends circumferentially about the central axis20 as shown in FIGS. 1 and 2. The turbine shroud 14 includes the carrier16 and the runner 18 (sometimes called a blade track) as shown in FIGS.3-8. The illustrative carrier 16 is a one-piece annular, round metalliccomponent and is configured to support the runner 18 in positionadjacent the blades 33 of the turbine wheel assembly 22. While thecarrier 16 is illustrated as an annular (full hoop) component, it may bemade up of a number of segments in other embodiments. The illustrativerunner 18 is an annular (full hoop) and round component. Theillustrative runner 18 is concentric with and nested into the carrier 16along the central axis 20. The runner 18 is arranged around the blades33 that rotate about the central axis 20 during operation of the gasturbine engine 10 and the runner 18 is blocked from rotating about thecentral axis 20 relative to the carrier 16 by insert pins 50 that couplethe runner 18 with the carrier 16 as shown in FIG. 8.

The annular runner 18 is illustratively made from a ceramic material;and, more particularly, a ceramic matrix composite (CMC) includingsilicon carbide fibers and silicon carbide matrix. For purposes of thisapplication, a ceramic material is any monolithic ceramic or compositein which at least one constituent is a ceramic. In other embodiments,the annular runner 18 may be made of other metallic, non-metallic, orcomposite materials with low coefficients of thermal expansion.

The annular runner 18 is illustratively a unitary component forming afull hoop as shown in FIG. 4. The annular runner 18 is a component ofone-piece, continuous construction, rather than as a series of joinedsegments. This integral construction eliminates gaps that may be formedbetween parts of a multi-piece (or segmented) runner. The one-piece fullhoop of the annular runner 18 encourages uniform radial expansion of theannular runner 18 at high temperatures. Uniform radial expansion of theannular runner 18 allows the annular runner 18 to remain round at hightemperatures which results in the ability to further maintain a smallgap between the blades 33 and the annular runner 18 while hot combustionproducts are being directed over the blades 33 and the annular runner18.

In illustrative embodiments, the carrier 16 is formed to include aplurality of outer pin receivers 32 arranged to receive the outer insertpins 30 as shown in FIGS. 5 and 7. The outer insert pins 30 extendthrough the turbine case 12 and into the outer pin receivers 32 formedin the carrier 16 to block rotation of the turbine shroud 14 about thecentral axis 20 relative to the turbine case 12. The outer insert pins30 may also block axial movement of the turbine shroud 14 along thecentral axis 20 relative to the turbine case 12. In some embodiments,the turbine shroud 14 does not include outer insert pins 30. In suchembodiments, the turbine shroud 14 may include at least one outer pinreceiver 32 (sometimes called a vent hole or a carrier aperture)arranged to receive a sensor 84.

The carrier 16 is formed to include an inwardly-opening carrier channel46 as shown in FIGS. 3, 5, and 7. The inwardly-opening carrier channel46 extends circumferentially around the central axis 20. Illustratively,the outer pin receivers 32 extend through the carrier 16 and open intothe carrier channel 46.

The carrier 16 includes an outer radial carrier surface 60 and an innerradial carrier surface 62 positioned radially between the central axis20 and the outer radial carrier surface 60 as shown in FIG. 5.Illustratively, each outer pin receiver 32 extends in a radial directionthrough the outer radial carrier surface 60 and the inner radial carriersurface 62 and opens into the inwardly-opening carrier channel 46. Inother embodiments, some or all of the outer pin receivers 32 extend in aradial direction partway through the carrier 16 from the outer radialcarrier surface 60 toward the inner radial carrier surface 62 of thecarrier 16.

The carrier 16 includes a forward section 38, an aft section 42 spacedapart axially from the forward section 38 relative to the central axis20, and a midsection 40 positioned axially between the forward section38 and the aft section 42 as shown in FIG. 5. In the illustrativeembodiment, the outer pin receivers 32 are formed in the midsection 40of the carrier 16 as shown in FIG. 5. The outer keyways 28 formed in theturbine case 12 are arranged to align axially with the outer pinreceivers 32 as shown in FIG. 7.

In some embodiments, the outer pin receivers 32 are located midwaycircumferentially between fuel nozzles included in the turbine 17. Thefuel nozzles may cause the turbine shroud 14 to have hot zones 45 asshown in FIG. 4. The hot zones 45 may be spaced apart circumferentiallyabout the turbine shroud 14.

In the illustrative embodiment, the carrier 16 is formed to include aplurality of bosses 70 as shown in FIG. 5. The bosses 70 are integrallyformed with the carrier 16 and extend radially outward away from thecarrier 16. The outer pin receivers 32 extend into the bosses 70 and theouter insert pins 30 extend through the bosses 70.

In the illustrative embodiment, the turbine 17 includes the plurality ofouter insert pins 30 as shown in FIGS. 4 and 7. The outer insert pins 30extend through the outer keyways 28 formed in the turbine case 12 andinto the outer pin receivers 32 formed in the carrier 16 to blockrotation of the carrier 16 relative to the turbine case 12 to providecentering of the carrier 16 to the turbine case 12 while allowing thecarrier 16 and the turbine case 12 to expand and contract at differentrates when the turbine shroud 14 is heated and cooled during operationof the engine 10. Accordingly the turbine case 12 and the carrier 16 maybe made from different materials that have different coefficients ofthermal expansion.

In the illustrative embodiment, one of the outer insert pins 30 is ahollow outer insert pin 30 formed to include a cooling passageway 44that extends radially through the hollow outer insert pin 30 as shown inFIG. 7. The inwardly-opening carrier channel 46 is exposed to fluidcommunication with air radially outwardly of the annular runner 18through the cooling passageway 44 formed in the hollow outer insert pin30. Illustratively, pressurized cooling air is directed through thehollow outer insert pin 30 through the turbine case 12 and the carrier16 into the carrier channel 46. In other embodiments, each of the outerinsert pins 30 is hollow. As a result, pressurized cooling air may bedirected through each of the hollow outer insert pins 30.

The annular runner 18 is aligned with the inwardly-opening carrierchannel 46 and is positioned close to the carrier 16 to define a bufferchamber 68 defined between by the annular runner 18 and the carrier 16as shown in FIGS. 3, 7, and 8. In the illustrative embodiment, theannular runner 18 is formed to include a plurality of inner pinreceivers 52 as shown in FIGS. 6 and 8. The plurality of inner pinreceivers 52 are spaced apart circumferentially about the central axis20 and sized to receive a plurality of inner insert pins 50 as suggestedin FIG. 4. Illustratively, the inner pin receivers 52 are spaced apartfrom the outer pin receivers 32 so that the inner pin receivers 52 arecircumferentially offset from the outer pin receivers 32.

The annular runner 18 includes an outer radial runner surface 64 and aninner radial runner surface 66 positioned radially between the centralaxis 20 and the outer radial runner surface 64 as shown in FIG. 6. Theillustrative inner pin receivers 52 extend in a radial direction partwaythrough the annular runner 18 from the outer radial runner surface 64toward the inner radial runner surface 66 of the annular runner 18 asshown in FIGS. 6 and 8.

The annular runner 18 includes a forward section 54, an aft section 58spaced apart axially from the forward section 54 relative to the centralaxis 20, and a midsection 56 positioned axially between the forwardsection 54 and the aft section 58 as shown in FIG. 6. In someembodiments, the inner pin receivers 52 are located midwaycircumferentially between the hot zones 45 caused by fuel nozzlesincluded in the turbine 17. Illustratively, the pressurized cooling airis supplied to the inwardly-opening carrier channel 46 to cool an outerradial runner surface 64 of the annular runner 18.

In other embodiments, the annular runner 18 includes a plurality ofbosses formed to include a corresponding pin receiver 52. The bossesextend outward radially away from the outer radial runner surface 64 ofthe annular runner 18 into the inwardly-opening carrier channel 46. Insome embodiments, the bosses are located in the midsection 56 of theannular runner 18.

In the illustrative embodiment, the turbine 17 includes the plurality ofinner insert pins 50 as shown in FIGS. 4 and 8. The inner insert pins 50extend through the inner keyways 48 formed in the carrier 16 and intothe inner pin receivers 52 formed in the annular runner 18 to blockrotation of the annular runner 18 relative to the carrier 16 to providecentering of the annular runner 18 to the carrier 16 while allowing theannular runner 18 and the carrier 16 to expand and contract at differentrates when the turbine shroud 14 is heated and cooled during operationof the engine 10. Accordingly the carrier 16 and the annular runner 18may be made from different materials that have different coefficients ofthermal expansion. In some embodiments, the gas turbine engine 10includes at least three inner insert pins 50 to locate the runner 18 inthree dimensions relative to the carrier 16.

According to at least one method of assembling the gas turbine engine10, the annular runner 18 is rotated to predetermined orientationrelative to the carrier 16 so that the inner pin receivers 52 formed inthe annular runner 18 are aligned with corresponding inner keyways 48formed in the carrier. The annular runner 18 is nested into the carrier16 so that the annular runner 18 is concentric with the carrier 16. Theinner insert pins 50 are placed into the corresponding inner keyways 48and inner pin receivers 52 to establish a connection between the annularrunner 18 and the carrier 16 and to provide the turbine shroud 14.

According to a method of assembling the gas turbine engine 10, theturbine shroud 14 is rotated to a predetermined orientation relative tothe turbine case 12 so that the outer pin receivers 32 formed in thecarrier 16 are aligned with the corresponding outer keyways 28 formed inthe turbine case 12. The turbine shroud 14 is nested into the turbinecase 12 so that the turbine shroud 14 is concentric with the turbinecase 12. The outer insert pins 30 are placed into the correspondingouter keyways 28 and the outer pin receivers 32 to establish aconnection between the turbine case 12 and the turbine shroud 14.

In the illustrative embodiments, the outer keyways 28, the outer pinreceivers 32, and the outer insert pins 30 are unthreaded as shown inFIGS. 5 and 7. In other embodiments, the outer keyways 28, the outer pinreceivers 32, and the outer insert pins 30 are threaded. In someembodiment, the outer pin receivers 32 include chamfered surfaces.

In the illustrative embodiments, the inner keyways 48, the inner pinreceivers 52, and the inner insert pins 50 are unthreaded as shown inFIGS. 6 and 8. In other embodiments, the inner keyways 48, the inner pinreceivers 52, and the inner insert pins 50 are threaded. In someembodiment, the inner pin receivers 52 include chamfered surfaces 53 asshown in FIG. 6. The inner insert pins 50 may block axial movement ofthe annular runner 18 along the central axis 20 relative to the carrier16.

In the illustrative embodiment, the outer pin receivers 32 have a largerdiameter than a diameter of the outer insert pins 30. In otherembodiments, the outer pin receivers 32 comprise slots. In someembodiments, the slotted outer pin receivers 32 have a larger axialdimension than a circumferential dimension relative to the central axis20. In some embodiments, the slotted outer pin receivers 32 extend fromthe midsection 40 partway into one or both of the forward section 38 andthe aft section 42.

In the illustrative embodiment, the inner pin receivers 52 have a largerdiameter than a diameter of the inner insert pins 50. In otherembodiments, the inner pin receivers 52 comprise slots. In someembodiments, the slotted inner pin receivers 52 have a larger axialdimension than a circumferential dimension relative to the central axis20. In some embodiments, the slotted pin receivers 52 extend from themidsection 56 partway into one or both of the forward section 54 and theaft section 58.

The cooling system 55 may include an optional annular impingement plate57 positioned in the buffer chamber 68 to separate the buffer chamber 68into an outer chamber 69 and an inner chamber 71 as shown in FIG. 7A.The inner chamber 71 is located radially between the outer chamber 69and the annular runner 18. At least one of the outer pin receivers 32opens into the outer chamber 69 to direct the pressurized cooling airinto the outer chamber 69. In the illustrative embodiment, pressurizedcooling air is directed through the hollow outer insert pin 30 and intothe outer chamber 69.

The illustrative impingement plate 57 includes a plurality of diffusionholes 59 that extend through the impingement plate 57 as shown in FIG.7A. The diffusion holes 59 are arranged to direct the pressurizedcooling air in the outer chamber 69 through the impingement plate 57into the inner chamber 71 and toward the outer radial runner surface 64of the annular runner 18. Illustratively, the diffusion holes 59 arespaced circumferentially around the impingement plate 57. In someembodiments, the diffusion holes 59 are formed to direct the pressurizedcooling air toward corresponding hot zones 45 of the annular runner 18.

The carrier 16 is formed to include a high-pressure cooling passage 80that extends through the carrier 16 as shown in FIG. 7A. Thehigh-pressure cooling passage 80 is configured to direct high-pressureair toward the forward section 38 of the annular runner 18. Thehigh-pressure air has a greater pressure than the pressurized coolingair. As a result, the forward section 38 of the annular runner 18 iscooled. In the illustrative embodiment, the diffusion holes 59 areformed to direct the pressurized cooling air toward at least one of theaft section 44 and the midsection 42 of the annular runner 18 as shownin FIG. 7A.

In the illustrative embodiment, the cooling system 55 further includesthe controller 90 and a valve 88 as shown in FIG. 7A. The controller 90is configured to modulate a flow rate of the pressurized cooling airdirected through the valve 88 into the outer chamber 69 to cause therunner 18 to expand and contract to control a radius of the runner 18.

According to at least one method of assembling a gas turbine enginehaving a cooling system, the impingement plate 57 is positioned in theradially inwardly-opening carrier channel 46 formed in the carrier 16 todefine the outer chamber 69. The runner 18 is coupled with the carrier16 to form the turbine shroud 14 and to close the carrier channel 46 todefine the inner chamber 71 located radially between the outer chamber69 and the runner 18. The turbine shroud 14 is coupled to the turbinecase 12 included in the gas turbine engine 10. The hollow outer insertpin 30 is inserted through the turbine case 12 and the carrier 16 intothe outer chamber 69 to provide the cooling passageway 44 through theturbine case 12 and the carrier 16 into the outer chamber 69.

In the illustrative embodiment, the gas turbine engine 10 includes ahealth monitoring system 82 as shown in FIGS. 3 and 7. The healthmonitoring system 82 includes at least one sensor 84. In some turbineshrouds, the air in the buffer chamber may be distributed unevenly. Asone example, turbine shrouds including segmented runners may allow thepressurized cooling air to leak between the runner segments which maycause uneven distribution of the air in the buffer chamber. As a result,it may be difficult for sensors to reliably measure properties of theair within internal chambers within segments.

The illustrative annular runner 18 is configured to result in generallyuniform distribution of the air in the buffer chamber 68. In theillustrative example, the annular runner 18 reduces air leakage byeliminating leakage between segments as the runner 18 is a one-pieceannular runner 18 without segments. Due to the generally uniformlydistributed air in the buffer chamber 68, a single sensor (or a smallnumber of sensors), such as pressure sensor 84, may be used to reliablymeasure properties of the air in the buffer chamber 68. The illustrativehealth monitoring 82 system includes the pressure sensor 84 arranged tomeasure an air pressure in the buffer chamber 68.

During operation of the gas turbine engine 10, the hot combustionproducts in the flow path 34 of the turbine 17 may damage and/or burnthrough a portion of the annular runner 18. As a result, unintentionalfluid communication is provided between the combustion products in theflow path 34 and the buffer chamber 68. The unintentional fluidcommunication causes a change in pressure in the buffer chamber 68 thatis detectable by the pressure sensor 84.

The pressure sensor 84 is located to monitor for changes in the pressurein the buffer chamber 68 which indicate that the annular runner 18 hasbeen compromised as suggested in FIG. 7. Illustratively, the pressuresensor 84 is arranged to monitor for changes which indicate thatunintentional fluid communication has been provided between the bufferchamber 68 and the flow path 34.

Illustratively, the health monitoring system 82 may be configured toalert an operator or engine control system of the gas turbine engine 10that the annular runner 18 is damaged based on information from thepressure sensor 84 so that the operator or engine control system mayrespond accordingly. For example, the operator or the engine controlsystem may direct additional cooling air to the annular runner 18,reduce a power of the engine 10, shut down the engine 10, scheduleinspection and repair of the engine 10.

In the illustrative embodiment, the pressure sensor 84 includes atransducer 92 and a pressure tube 94 as shown in FIG. 7. The pressuretube includes a first end 95 coupled to the transducer 92 and a secondend 96 in fluid communication with the buffer chamber 68. In someembodiments, the transducer 92 is located outside of the buffer chamber68 and the second end 96 of the pressure tube 94 extends into one of theouter pin receivers 32 and opens into the buffer chamber 68. In theillustrative embodiment, the transducer 92 is coupled to the turbinecase 12 and the pressure tube extends through the hollow outer insertpin 30. In the illustrative embodiment, the pressure tube 94 extendsinto the buffer chamber 68. In other embodiments, the pressure tube 94opens into the buffer chamber 68 without extending into the bufferchamber 68.

In the illustrate embodiment, the health monitoring system 82 furtherincludes a conduit 86, the valve 88, and the controller 90 as shown inFIGS. 3 and 7. The conduit 86 is in fluid communication with the bufferchamber 68 to direct pressurized cooling air through the turbine case 12and the carrier 16 into the buffer chamber 68. The valve 88 is connectedto the conduit 86. The controller 90 is coupled to the valve 88 to openand close the valve 88 in response to signals received from the pressuresensor 84 to modulate the pressurized cooling air directed into thebuffer chamber 68.

In the illustrative embodiment, the conduit 86 is coupled to a hollowouter insert pin 30 as shown in FIG. 7. In other embodiments, theconduit 86 extends through one of the outer keyways 28 formed in theturbine case 12 and opens into the buffer chamber 68 to directpressurized cooling air through the turbine case 12 and the carrier 16into the buffer chamber 68. In the illustrative embodiment, thecontroller 90 and the valve 88 are positioned radially outside theturbine case 12 to locate the turbine case 12 between the controller 90and the central axis 20.

In the illustrative embodiment, the compressor 13 supplies thepressurized cooling air to the conduit 86. In the illustrativeembodiment, interstage compressor air, sometimes called intermediatestage air, is supplied to the conduit 86 by the compressor 13. In someembodiments, compressor discharge air having a higher pressure than theinterstage compressor air is supplied to the conduit 86 by thecompressor. Illustratively, interstage compressor air is drawn from anintermediate stage of the compressor 13 and the compressor discharge airis drawn from a compressor stage downstream of the intermediate stage.Illustratively, the compressor discharge air is drawn from the laststage of the compressor 13.

The controller 90 is configured to actively adjust the valve 88 duringoperation of the engine 10. As one example, the controller 90 isarranged to actively adjust the valve 88 between the opened and closedposition to regulate a flow of the pressurized cooling air. As anotherexample, the controller 90 is arranged to fully open and fully close thevalve 88 to regulate a flow of the pressurized cooling air. In someembodiments, the health monitoring system 82 includes a high speedcontroller and a high speed valve 88.

In some embodiments, the controller 90 is configured to fully close thevalve 88 in response to the signals received from the pressure sensor 84being indicative of the air pressure in the buffer chamber 68 beingbelow a predetermined threshold pressure. As an example, high pressureair, such as compressor discharge air, having a higher pressure than thepressurized cooling air is directed toward the forward section 38 of theannular runner 18 through a high-pressure cooling passage 80 in someembodiments. If the annular runner 18 is compromised, the high pressureair may be used to purge the buffer chamber 68 and the valve 88 may beclosed to block the high pressure air and the combustion products fromflowing through the conduit 86 toward the compressor 13.

In some embodiments, the controller 90 is configured to fully open thevalve 88 in response to the signals received from the pressure sensor 84being indicative of the air pressure in the buffer chamber 68 beingbelow a predetermined threshold pressure. As an example, high pressureair, such as compressor discharge air, having a relative high pressureis directed through the conduit 86 toward the annular runner 18 in someembodiments. If the annular runner 18 is compromised, the valve 88 maybe fully opened to allow the high pressure pressurized cooling air topurge the buffer chamber 68.

In some embodiments, the health monitoring system further includes atemperature sensor 98 as shown in FIG. 7. The temperature sensor 98 isconfigured to measure a temperature in the buffer chamber 68. Thecontroller 90 is configured to receive signals from the temperaturesensor 98 and to open and close the valve 88 in response to the signalsreceived from the temperature sensor 98 to modulate the pressurizedcooling air directed into the buffer chamber 68.

According to at least one method of controlling the health monitoringsystem 82, pressurized cooling air is directed into the buffer chamber68 formed between the carrier 16 and the annular runner 18. The bufferchamber 68 is configured to route the pressurized cooling air around theannular runner 18. The air pressure in the buffer chamber 68 ismeasured. The pressurized cooling air directed into the buffer chamber68 is controlled in response to the air pressure measurements.

In the illustrative embodiment, the turbine shroud 14 further includes afirst forward seal 72, a second forward seal 73, and an aft seal 74 asshown in FIGS. 3, 7, and 9-13. The seals 72, 73, 74 are positionedbetween the carrier 16 and the annular runner 18 to block combustionproducts from flowing out of the flow path 34 and over the outer radialrunner surface 64 of the annular runner 18. The seals 72, 73, 74 arearranged to maintain contact with the annular runner 18 as the carrier16 and annular runner 18 move radially due to thermal expansion. In someembodiments, the seals 72, 73, 74 are pre-loaded into a compressedstate.

In an illustrative embodiment, the carrier 16 is formed to include afirst inwardly-facing forward seal receiver 76, a second inwardly-facingforward seal receiver 77, and an inwardly-facing aft seal receiver 78 asshown in FIGS. 5 and 7. The first and second forward seal receivers 76,77 are axially aligned with the forward section 54 of the annular runner18 and receive corresponding seals 72, 73. The aft seal receiver 78 isaligned with the aft section 58 of the annular runner 18 and receivesseal 74. The annular runner 18 is located radially inward of the forwardand aft seal receivers 76, 77, 78 and engage the seals 72, 73, 74.

In illustrative embodiments, the carrier 16 is formed to include thehigh-pressure cooling passage 80 as shown in FIGS. 5 and 7. Thehigh-pressure cooling passage 80 is arranged to receive high pressurecooling air and to direct the high pressure cooling air toward theannular runner 18. The high-pressure air has a greater pressure than thepressurized cooling air directed through the inner pin receivers 52.

Illustratively, the high-pressure cooling passage 80 is formed in theforward section 38 of the carrier 16 and directs the high pressurecooling air toward the forward section 54 of the outer radial runnersurface 64 of the annular runner 18 as shown in FIGS. 5 and 7. In theillustrative embodiment, the first forward seal 72 is spaced apartaxially from the second forward seal 73 to locate the high-pressurecooling passage between the first and second forward seals 72, 73. Theaft seal 74 is spaced apart axially from the second forward seal 73 tolocate the buffer chamber 68 therebetween.

A portion of the high-pressure cooling air blocks combustion products inthe flow path 34 from passing between the annular runner 18 and thecarrier 16 at the forward end of the turbine shroud 14 as suggested inFIG. 7. A portion of the high-pressure cooling air is directed aft intothe buffer chamber 68. The high-pressure cooling air in the bufferchamber 68 may exit the buffer chamber 68 at the aft end of the carrier16 and annular runner 18 and block combustion products in the flow path34 from passing between the annular runner 18 and the carrier 16 at theaft end of the turbine shroud 14.

In illustrative embodiments, the seals 72, 73, 74 are piston ring sealsas shown in FIG. 7. In some embodiments, the piston ring seals 72, 73,74 comprise ceramic matrix composite material. In other embodiments, theseals 72, 73, 74 comprise O-rings 72, 73, 74 in place of the piston ringseals. In some embodiments, the seals 72, 73, 74 are C-shaped seals andreplace the piston ring seals as shown in FIGS. 11 and 12. In someembodiments, one or more of the seals 72, 73, 74 are W-shaped andreplace the piston ring seals as shown in FIG. 13. As shown in FIG. 13,in some embodiments, the carrier 16 includes one forward seal receiver76 and the W-shaped seal 72 is positioned in the forward seal receiver76. In some embodiments, each seal 72, 73, 74 is a full hoop. In otherembodiments, each seal 72, 73, 74 is formed from a number of sealsections. In some embodiments, the seals 72, 73, 74 comprise ceramicmatrix composite material. In some embodiments, the seals 72, 73, 74 areformed to include through holes to allow a predetermined flow of airthrough the seals 72, 73, 74.

This application cross-references U.S. Patent Application PublicationNumber 2017/0204736 titled GAS TURBINE ENGINE WITH HEALTH MONITORINGSYSTEM which published on Jul. 20, 2017, filed concurrently herewith andU.S. Patent Application Publication Number 2017/0204744 titled TURBINESHROUD WITH MOUNTED FULL HOOP BLADE TRACK which published on Jul. 20.2017, filed concurrently herewith, the disclosures of which are nowexpressly incorporated herein by reference. The subject matter disclosedin those references, including the claimed subject matter, is includedherein such that the present disclosure includes each of the featuresand combinations thereof.

While the disclosure has been illustrated and described in detail in theforegoing drawings and description, the same is to be considered asexemplary and not restrictive in character, it being understood thatonly illustrative embodiments thereof have been shown and described andthat all changes and modifications that come within the spirit of thedisclosure are desired to be protected.

What is claimed is:
 1. A turbine shroud for use in a gas turbine enginehaving a central axis, the turbine shroud comprising an annular carrierformed to define a radially inwardly-opening carrier channel thatextends around the central axis and the annular carrier includes anouter pin receiver that extends through the annular carrier and opensinto the carrier channel to allow pressurized cooling air to passthrough the annular carrier into the carrier channel and a high-pressurecooling air passageway that extends radially through the annularcarrier, a one-piece annular runner aligned axially with the carrierchannel of the annular carrier, the one-piece annular runner includes aninner radial runner surface located radially between the annular carrierand the central axis and an outer radial runner surface located radiallybetween the inner radial runner surface and the annular carrier, and theouter radial runner surface cooperates with the annular carrier to forman annular buffer chamber between the annular carrier and the one-pieceannular runner, and a cooling system including an annular impingementplate positioned in the annular buffer chamber to separate the annularbuffer chamber into an outer chamber and an inner chamber locatedradially between the outer chamber and the one-piece annular runner, theouter pin receiver opens into the outer chamber to direct thepressurized cooling air into the outer chamber, and the annularimpingement plate includes a plurality of diffusion holes spacedcircumferentially around the annular impingement plate and eachdiffusion hole extends radially through the impingement plate to directthe pressurized cooling air in the outer chamber through the annularimpingement plate into the inner chamber and toward the outer radialrunner surface of the one-piece annular runner, wherein the one-pieceannular runner includes a forward section, an aft section spaced apartaxially from the forward section, and a midsection extending between theforward section and the aft section, the high-pressure cooling airpassageway is configured to direct high-pressure air toward the forwardsection of the one-piece annular runner, the high-pressure air has agreater pressure than the pressurized cooling air, and the turbineshroud further includes a first seal positioned radially between theone-piece annular runner and the annular carrier and positioned axiallybetween the high-pressure cooling air passageway and the annular bufferchamber.
 2. The turbine shroud of claim 1, wherein the one-piece annularrunner includes circumferentially spaced apart hot zones associated withrelatively high temperatures during operation of the gas turbine engineand each diffusion hole formed in the annular impingement plate isarranged to direct the pressurized cooling air toward a correspondinghot zone.
 3. The turbine shroud of claim 1, wherein the diffusion holesformed in the annular impingement plate are arranged to direct thepressurized cooling air toward at least one of the aft section and themidsection.
 4. The turbine shroud of claim 1, wherein the gas turbineengine includes a turbine case arranged around the annular carrier, thecooling system further includes a hollow insert pin configured to extendthrough the turbine case and the outer pin receiver formed in theannular carrier to couple the annular carrier to the turbine case, andthe hollow insert pin is configured to direct the pressurized coolingair through the turbine case and the annular carrier into the outerchamber.
 5. The turbine shroud of claim 4, wherein the cooling systemfurther includes a controller configured to modulate a flow rate of thepressurized cooling air directed through the hollow insert pin into theouter chamber to control an expansion and contraction of the one-pieceannular runner.
 6. The turbine shroud of claim 4, further including asecond seal positioned between the outer radial runner surface of theone-piece annular runner and the annular carrier to block thepressurized cooling air from escaping the inner chamber and the secondseal is positioned axially aft of the first seal to locate the annularbuffer chamber axially between the first seal and the second seal. 7.The turbine shroud of claim 6, wherein the second seal includes a pistonring made from one of a metallic material, a ceramic material, and aceramic matrix composite material.
 8. A gas turbine engine comprising aturbine case arranged around a central axis of the gas turbine engine,the turbine case includes one or more outer keyways that extend throughthe turbine case, a turbine shroud including (i) a carrier formed todefine a radially inwardly-opening carrier channel that extends aroundthe central axis and one or more outer pin receivers that extend throughthe carrier and open into the carrier channel and (ii) an annular runneraligned axially with the carrier and positioned to close theinwardly-opening carrier channel to form an annular buffer chamberbetween the carrier and the annular runner, and a cooling systemincluding one or more hollow outer insert pins that extend through thecorresponding one or more outer keyways formed in the turbine case andthe one or more outer pin receivers formed in the carrier into thebuffer chamber to allow pressurized cooling air to pass through theturbine case and the carrier into the buffer chamber, wherein theannular runner includes a forward section, an aft section spaced apartaxially from the forward section, and a midsection extending between theforward section and the aft section, the carrier is formed to include ahigh-pressure cooling air passageway that extends through the carrierand is configured to direct high-pressure air toward the forward sectionof the annular runner, and the high-pressure air has a greater pressurethan the pressurized cooling air, wherein the gas turbine engine furtherincludes a first seal positioned radially between the annular runner andthe carrier and positioned axially between the high-pressure cooling airpassageway and the buffer chamber.
 9. The gas turbine engine of claim 8,further including a second seal positioned radially between the annularrunner and the carrier and positioned axially aft of the first seal tolocate the buffer chamber axially between the first and the second sealand each of the first seal and the second seal includes a piston ringmade from one of a ceramic and a ceramic matrix composite material. 10.The gas turbine engine of claim 8, wherein the cooling system furtherincludes an impingement plate positioned in the annular buffer chamberto separate the annular buffer chamber into an outer chamber and aninner chamber located radially between the outer chamber and the annularrunner, the one or more hollow outer insert pins is in fluidcommunication with the outer chamber to direct the pressurized coolingair into the outer chamber, and the impingement plate includes aplurality of diffusion holes spaced apart circumferentially around theimpingement plate that extend radially through the impingement plate todirect the pressurized cooling air in the outer chamber through theimpingement plate into the inner chamber and toward the annular runner.11. The gas turbine engine of claim 10, wherein the annular runnerincludes circumferentially spaced apart hot zones associated withrelatively high temperatures during operation of the gas turbine engineand each diffusion hole is formed to direct the pressurized cooling airtoward a corresponding hot zone.
 12. The gas turbine engine of claim 10,wherein the plurality of diffusion holes are arranged to direct thepressurized cooling air toward at least one of the aft section and themidsection.
 13. The gas turbine engine of claim 10, further comprising acompressor, the pressurized cooling air is supplied by an intermediatestage of the compressor, and the high-pressure air is supplied by acompressor stage located downstream of the intermediate stage.
 14. Thegas turbine engine of claim 8, further comprising a compressor and thepressurized cooling air is supplied by an intermediate stage of thecompressor.
 15. The gas turbine engine of claim 8, wherein the coolingsystem further includes a controller configured to modulate a flow rateof the pressurized cooling air directed through the one or more hollowouter insert pins into the buffer chamber and the controller is coupledto an outer surface of the turbine case.